Cbm 2001 Pet strange boot

[Desperado]

Yes, but which one (bearing in mind it is data bit 0)?

Dave

This is very difficult question for me Dave

 

[Nivag Swerdna]

Nivag, I suspect you may also have a bug in your own code for displaying the hexadecimal letters A through F?

? I assumed it was a funny character only due to the floating GRAPHIC line which was due to the VIA? Bugs are likely though.. I haven't written 6502 assembly since 1980

 

[Nivag Swerdna]

OK... prepare yourself for Configuration ERIC...

Get labels and stick E7 on chip E7, E8 on E8. And now swap E7 to be in socket E8 and E8 to be in Socket E7. Otherwise don't change anything!

Post a photo... of your lovely stickers on the chips on the board and the resulting screen

When changing chips be super careful not to bend legs when re-inserting them, make sure all are nicely back in their sockets. It is very easy to introduce extra issues due to deperation!

 

[daver2]

>>> I assumed it was a funny character only due to the floating GRAPHIC line which was due to the VIA.

Yep.

I like your thinking in post #503...

Dave

 

[Desperado]

ERIC configuration:

 

[Nivag Swerdna]

ERIC configuration:

Good stuff. Now put stickers on E9 and E10... swap them... take more photos. Leave E7 and E8 swapped as per current state.

Call this swapped configuration.... Configuration FANDANGO

 

[Desperado]

Now put stickers on B3 and C3... swap them

To do this i need to unsold the two ics

 

[Nivag Swerdna]

To do this i need to unsold the two ics

OOPS Sorry... please see my revised post above..... I meant E9 and E10! (We know B3 and C3 are behaving... sorry for that mental outage)

 

[Desperado]

OOPS Sorry... please see my revised post above..... I meant E9 and E10! (We know B3 and C3 are behaving... sorry for that mental outage)

Always the same...ics solded on board

 

[Nivag Swerdna]

How about I10 and I11? Are they socketed?

 

[daver2]

To save you desoldering two ICs - should he desolder E9 first, install a socket and try a replacement buffer (after labelling the original as E9 first)?

Dave

 

[Desperado]

How about I10 and I11? Are they socketed?

Not...solded on board too

 

[Nivag Swerdna]

Not...solded on board too

OK. So the suspicion is that E9 may be an issue (although there may be contention from I10). You should socket E9 at least. Feel free to destroy the existing chip if it makes desoldering easier... i.e. snip legs and then desolder one at a time.

Get it socketed and a new 74LS244 into E9 and then report back.

We can call that new configuration Configuration GERONIMO

 

[Desperado]

Im Desperate!! this is GERONOMO config but i have always bad screen

 

[daver2]

What do you mean, “you always have a bad screen”. It’s working!

Although I suspect there may be a bug in Nivag’s code...

Compare what you have now with Nivag’s post back in #495.

Dave

 

[Desperado]

What do you mean, “you always have a bad screen”. It’s working!

Although I suspect there may be a bug in Nivag’s code...

Compare what you have now with Nivag’s post back in #495.

Dave

it is true! I had not seen that now the numbers indicate 59!
Super!!

 

[daver2]

You have to stop, look and think before getting despondent and posting that you are desperate!

Now, let’s go for broke (configuration HOTEL) by removing Nivag’s magic ROM from UD9 and inserting Nivag’s version of the PETTESTER ROM (the one we used in configuration CHARLIE back in post #447) into UD9 and posting a picture.

Hopefully, now, it will pass the video RAM test!

We still have some chips removed (and a couple swapped over) - but that’s OK for now - since we know what we have done because we have it documented!

Dave

 

[Desperado]

ok this is HOTEL config:

 

[Nivag Swerdna]

Pre-empted! You never tried my follow up!

Anyway... looking good!

 

[Nivag Swerdna]

Anyway... concerning Configuration HOTEL. Please take a photo of all the ROM slots.... I would like to see what we have!

Also. please confirm this is 000039DB ROM ( actually I see DD67... and UD9.bin shows F=DD67 )

Let the count go to zero.... and see what happens...